Automatic circuit-breaking system



May 21, 1929. H. BENIT AUTOHATIC cmcum' BREAKING SYSTEM 2 Sheets-Sheet 1 Filed Jan. 13, 1927 five/d0! firm i Z a/zit Attorney May 21, 1929. H. BENIT 1,714,415

' AUTOMATIC CIRCUIT BREAKING SYSTEM Filed Jan. 13, 1927 2 Sheets-Sheet 2 Patented May 21, 1929.

UNITED STATES 1,714,415 PATENT OFFICE.

HENRI BENIT, OF PARIS, FRANCE.

AUTOMATIC CIRCUIT-BREAKING SYSTEM.

Application filed January 13, 1927, Serial No. 160,979, and in Germany January 29, 1926.

In a generating station when a short circuit takes place on a feeder, this feeder may have to deal with the full short circuit current which the generators are able to supply at that moment, if the short circuit occurs near to the station.

Therefore the circuit breaker placed on th feeder for .the purpose of breaking this short circuit, must have a rupturing capacity corresponding to the full short circuit current of the whole of the station.

A generating station with a large .number of feeders must therefore be provided with a large number of high capacity circuit breakers which only operate at rare intervals.

The purpose of the system which is the object of the present invention is to do away with these circuit breakers and to replace them by a single breaking system to which the short circuited feeder is connected by means of a suitable switching arrangement at the moment it becomes necessary to break the circuit. Y

e invention is diagrammatically illustrated in the accompanying drawings.

In order to simplify the diagrams only one of the conductors of the circuits has been shown, the invention being applied in the same manner for single phase, two and three phase current.

Figure 1 is a diagrammatic view of the assembled system, and

Figure 2 is a modified arrangement of the transferring switches.

References to these views will now be made by means of like characters corresponding to similar parts throughout.

1 are the usual main bus bars of the station;

2 are the alternators feeding these bars;

3, 3, 3 are the various feeders; v

4, 4, 4 are switching devices which are in the position shown in 4 when the station is operating normally, establishing communication between the feeder 3 and the main bus bars 1. In moving towards the right these switches connect the feeder 3 with a second set of bars 5, which may be called interruption bars (without first breaking the connection with the bus bars 1) and then, by continuing their movement, break the connection between the main bus bars 1 and the feeder 3" which, as shown in 1", thus remalns 1n communication only with the interruption which opens and breaks the circuit as soon as the switch 4 has reached its extreme towards the right.

As a large number of this circuit'breaker 6 are not required it may without involvin undue expense be of very solid design and ave a very liberally calculated interrupting capacity.

The opening of the circuitbreaker 6 is effected by the switch 4:" itself which at the end of its stroke makes contact at 7 allowing current from a source of supply 9 to pass through the releasing coil 8 of the circuit breaker 6.

The switching device 4 is operated in the usual manner by an overload relay 10.

It will be noted that the operation of the device 4 can only take place when the circuit breaker 6 is closed since the contacts 16 are then shorted and the coils 17 energized to keep the cores 18 in an extended position in the path of switches 4; and that this circuit breaker itself can not open unless the switch has connected the feeder to the interruption ars.

position interrupt any current they may be of very simple design either of the sliding contact type as shown diagrammatically on Fig 1, or they may consist of two separate circuit breakers as shown in Fig. 2. v

These two circuit breakers 11 and 12 are intended to connect the feeder 3 with the main bus bars 1 and with the interruption bars 5 respectively. Thus when the feeder isworking normally the circuit breaker 11 alone is closed.

If a short circuit takes place the relay 10 first closes the circuit breaker 12 (position shown in the figure) and then the latter in closing causes the current from the source of supply 14: to flow through the contacts 13 to the releasing mechanism of the circuit breaker 11 which at the end of the stroke of the core 11 frees said mechanism and closes the contact 15; this allows current to flow through the coil- 8 of the circuit breaker 6 and, consequently, causesthe latter to open.

The bus bars 1 and 5, instead of being single as shown in the figure, should of course be double as is customary in all high tension plants, the various apparatus being switched onto one or the other set of bars by means of two sets of disconnecting As the switching devices 4 do not have to switches. For-safety and maintenance purposes two circuit breakers may also be provided in place of the single circuit breaker 6 shown in the figures, one or the other of which is put into service by means of dis- I connecting switches, as above.

' Finally the circuit breaker 6,'in stead of being an ordinary breaking apparatus as shown diagrammatically in the figures, may be designed in such a way that resistances or inductances are inserted progressively so as to gradually reduce the current before the circuit is broken.

Having thus fully described the invention,:

what I- claim as new and desire to'protect by Letters Patent is: I

1. A circuit breaking system for an electric generating station comprising va main feeder from the main bus to an interruption bar connected to the main bus bars through said circuit breaker.

2. 'A circuit breaking system for the main feeders of an electric generating station,

characterized by the use, of asingle circuit.

breaker for disconnecting any defective feeder in case of short circuit, switching de-' vices controlled by overload relays inductively coupled to a corresponding coil in series witheach feeder, said switching device automatically transferring a faulty feeder from the main bus barsof the station to an interruption bar connected tothe main bus bars through said circuit breaker, and means forcontrolling the operation of the circuit breaker so that the switching of a faulty feeder to the interruption bars cannot be done unless the circuit breaker is closed, and that thecircuit breaker cannot open until the faulty feeder has been switched over to the said interruption bars.

In witness whereof I have hereunto set my hand.

HENRI BENIT. v 

